Self-reported health is a commonly used general measure of population health and is frequently used to illustrate health disparities between members of different racial and ethnic groups. Although Latinos report "fair" or "poor" health at levels comparable to those of African Americans, other measures of health and functional status show they may have less need for health care, and their age-adjusted mortality rate is significantly lower than that of non-Latino whites. The central hypothesis of this study is that acculturation level influences how Latinos report their health perceptions. This study has three specific aims: 1) To measure the extent to which acculturation explains differences in self-assessed health between Latinos and non-Latino whites residing in California; 2) To measure the association of various indicators of acculturation with self-assessed health among Latinos and members of Latino subgroups; and 3) To evaluate the conceptual equivalence of self-reported health measures between Latinos and non-Latino whites, and among Latino subgroups. The study will employ a cross-sectional design, using data from the 2001 California Health Interview Survey, which includes interviews from a geographically stratified random sample of nearly 11,000 Latinos and 26,000 non-Latino whites ages 18-64. The first two aims will be addressed by using multivariate analysis to model self-assessed health as a function of demographic, SES, acculturation, access barriers, health conditions, and contextual SES factors, using the general health question, Physical Component Score, and Mental Component Score of the SF-12 as outcome measures. The third aim will be explored using factor analysis of the SF-12 to compare these self-assessed health constructs for Latinos vs. non-Latino whites, and for disadvantaged persons vs. others. This will be one of very few population-based studies to include measures of both acculturation and chronic health conditions in multivariate assessment of health status. The findings will suggest whether self-reported health, as currently measured, is a valid indicator of health status or need for physical health services in a diverse population.